1. Technical Field
The present invention relates to a rotary machine, and more particularly, to a horizontally oriented rotary machine having an internal lubrication oil pump.
2. Description of the Prior Art
A rotary machine, such as a scroll type refrigerant compressor, which is horizontally oriented is disclosed in U.S. Pat. No. 4,917,582 issued to Fraser, Jr. et al. In Fraser, the horizontally oriented scroll type refrigerant compressor includes an internal lubrication oil pump which functions to supply lubrication oil in an oil sump of a compressor casing to the frictional surfaces of the internal component parts of the compressor. The oil pump operates by virtue of the reciprocating motion of one component part of an Oldham coupling mechanism which is used for preventing the rotation of an orbiting scroll member.
In comparison with a vertically oriented scroll type refrigerant compressor having an internal lubrication oil pump as disclosed in Japanese Patent Application Publication No. 6-336076, the teaching of the Fraser patent can reduce the size of the compressor. In particular, the height of the compressor can be remarkably reduced.
However, the oil pump disclosed in the Fraser patent can not be applied to scroll type refrigerant compressors having a non-Oldham coupling type rotation preventing mechanism (e.g., a ball coupling type rotation preventing mechanism) because the oil pump can only operate by virtue of the reciprocating motion of one component part of the Oldham coupling mechanism.
Furthermore, in the Fraser patent, one member which is rotatable with a drive shaft, such as a balancing weight which is fixedly connected to the drive shaft, may pass through the lubrication oil in the oil sump located at an inner bottom portion of the compressor casing when a level of the lubrication oil in the oil sump is excessively increased. This causes a defective torque fluctuation and ineffective operation of the drive shaft due to oil viscous drag.